Sleep problems may mediate associations between rumination and PTSD and depressive symptoms among OIF/OEF veterans

Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) veterans have high rates of posttraumatic stress disorder (PTSD), depression, and sleep problems. Identifying potential contributing factors to these mental health problems is crucial for improving treatments in this population. Rumination, or repeated thoughts about negative experiences, is associated with worse PTSD, depression, and sleep problems in nonveterans. Therefore, we hypothesized that rumination would be associated with worse sleep problems, PTSD, and depressive symptoms in OIF/OEF veterans. Additionally, we proposed a novel hypothesis that sleep problems are a mechanism by which rumination contributes to depressive and PTSD symptoms. In this cross-sectional study, 89 OIF/OEF veterans completed measures of trait rumination, sleep problems, and PTSD and depressive symptoms. Analyses confirmed that greater rumination was associated with worse functioning on all mental health measures. Moreover, greater global sleep problems statistically mediated the association between higher rumination and more PTSD and depressive symptoms. Specifically, sleep disturbance and daytime somnolence but not sleep quantity emerged as significant mediators. Although it is impossible with the current nonexperimental data to test causal mediation, these results support the idea that rumination could contribute to impaired sleep, which in turn could contribute to psychological symptoms. We suggest that interventions targeting both rumination and sleep problems may be an effective way to treat OIF/OEF veterans with PTSD or depressive symptoms.